Department of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece.
Int J Sports Med. 2021 Jul;42(9):818-824. doi: 10.1055/a-1342-7446. Epub 2021 Jan 27.
The purpose of the study was to define the most appropriate method for the calculation of the speed corresponding to lactate threshold (sLT) in male swimmers. Eight boys and eight adolescents (age: 11.4±0.5 and 15.8±0.8 years) performed 7×200-m swimming front-crawl and after drawing the speed lactate curve, the sLTs were calculated using five methods: i) the intersection of two linear regression lines, ii) visual inspection, iii) D-max, iv) D-max modified, v) intersection of combined linear and exponential regression lines. All methods were compared to the speed corresponding to maximal lactate steady state (sMLSS). Two to four 30-min efforts of continuous swimming at imposed constant pace were used for sMLSS calculation. In both groups, speed of D-max modified was similar to sMLSS (children, 1.061±0.073 . sMLSS: 1.071±0.072 m·s; p>0.05; effect size: ES=0.15, small; adolescents, 1.318±0.060 . sMLSS: 1.284±0.047 m·s; p>0.05; ES=0.64, medium). In adolescents, sLT calculated by intersection of two regression lines and by visual inspection presented medium ES (0.22-0.24) and were no different to sMLSS (1.296 ± 0.051, 1.295±0.053 m·s, p>0.05). When testing children, D-max modified is the most appropriate method to estimate sMLSS. The intersection of the linear regression lines and visual inspection are suggested for sMLSS determination in adolescents.
本研究旨在确定计算男性游泳运动员乳酸阈速度（sLT）的最适方法。8 名男孩和 8 名青少年（年龄：11.4±0.5 岁和 15.8±0.8 岁）进行了 7×200 米游泳爬泳，在绘制速度-乳酸曲线后，使用五种方法计算 sLT：i）两条线性回归线的交点，ii）视觉检查，iii）D-max，iv）修改后的 D-max，v）组合线性和指数回归线的交点。所有方法均与最大乳酸稳态速度（sMLSS）进行比较。使用 2 到 4 次持续 30 分钟的恒定速度游泳努力来计算 sMLSS。在两个组中，修改后的 D-max 速度与 sMLSS 相似（儿童，1.061±0.073. sMLSS：1.071±0.072 m·s；p>0.05；效应量：ES=0.15，小；青少年，1.318±0.060. sMLSS：1.284±0.047 m·s；p>0.05；ES=0.64，中）。在青少年中，两条回归线交点和视觉检查计算的 sLT 具有中等 ES（0.22-0.24），与 sMLSS 无差异（1.296 ± 0.051，1.295±0.053 m·s，p>0.05）。在测试儿童时，修改后的 D-max 是估计 sMLSS 的最适方法。线性回归线交点和视觉检查适用于青少年 sMLSS 的确定。
